JPS59215256A - Continuous casting method in twin roll type continuous casting machine - Google Patents

Abstract

PURPOSE:To prevent crazing, etc. of a metallic strip and to improve the quality of a product by measuring the rolling down force with which the rolls of a twin roll type continuous casting machine roll down a solidified layer, comparing the rolling down force with a set value and adjusting the position of barrel seals. CONSTITUTION:A twin roll type continuous casting machine obtains a thick metallic strip 9 of a prescribed roll gap G by rotating screw shafts 14, 15 to move horizontally and parallel disposed rolls 1, 2 to the right and left and to form said gap G, supplying a molten steel 7 into the space enclosed with barrel seals 3, 4 and side seals 5 disposed on the top and side faces of the gap, rotating the rolls 1, 2 to cool and solidify the molten steel and rolling a solidified layer 8 formed by such cooling by the rolls 1, 2. The rolling down force in the above- mentioned rolling with such casting machine is measured with load detectors 12, 13 such as load cells and when the rolling down force is larger than the set value, the barrel seals 3, 4 are moved to the roll gap side by fluid pressure cylinders 16, 17 to reduce the cooling length L of the steel 7. The cooling length is increased when the rolling down force is smaller than the set value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous casting method using a twin-roll continuous casting machine that can improve product quality by preventing cracks from occurring in metal strips.

In recent years, various methods have been proposed for continuously casting metal strips using a twin-roll continuous casting machine. The continuous casting method using such a twin-roll continuous casting machine will be explained with reference to FIGS. The gap G between the rolls (1) and (2) can also be adjusted using a screw or the like according to the thickness of the metal strip (9). Moreover, barrel seals (3H4) for storing the molten steel (7) are provided on the rolls (1) and (2), and the molten steel (7) is placed on both sides of the roll (11 (21).
) is provided with side/rules (5) to prevent leakage to both sides. The side seal (5) can swing in the direction of the roll axis '831 using its upper end as a fulcrum, and the side seal (5) is rotated by the fluid pressure cylinder (6).
5) is pressed against the side of the roll with a constant force.

When casting metal strips using the above twin-roll continuous @ machine,
Adjust the gap G between the left and right rolls (]) (]2 to a predetermined gap corresponding to the plate thickness, drive the drive unit fK, 1: Re-roll (1) (2) fully drive, and seal the barrel (3).
(4) Molten steel is supplied by an appropriate means to the space above the rolls (1) and (2) formed by the molten steel seal (5), and is cooled by the surface of the rolls (]) and (2). The formed coagulated layer (8) is continuously pulled out from between the rolls (1) (21).

As a result, metal strips are continuously cast.

However, in the above casting method, it is the rolls (1) and (2) that cool the molten steel (7) and form the solidified layer (8).
The side seal (5) has almost no function of cooling the molten steel (7). For this reason, the coagulated layer (8) is pulled out from the roll (]) (21) and the coagulated layer (8) is pulled out from the roll (1) (2
), the cooling rate of the solidified layer (8) decreases significantly. Therefore, the lowest end position of the unsolidified layer, that is, the uppermost position P where the molten steel (7) solidifies over the entire thickness direction of the metal strip, is the same as the center position of the rolls (1) and (2), or is the same as the center position of the rolls (]) ( If the metal strip is not positioned above the center position of 2), the unsolidified layer present in the pulled metal strip will leak from both sides in the width direction of the metal strip, causing burrs on the end surface or changing the shape of the end surface. becomes defective, which significantly reduces the product quality of the metal strip and leads to a decrease in yield.

Therefore, in the above continuous casting method, the roll (1)
The speed of roll (1) (2+) is adjusted so that the molten steel completely solidifies at or above the center position of roll (2).
) When it solidifies completely above the center position in (2),
The thickness of the solidified layer (8) is larger than that of the metal strip (9), so the gap G between the rolls (1) and (2)
When passing through, it is rolled by rolls (11(2)).

There is no problem if the rolling blade during such rolling is smaller than a predetermined value, but if the thickness of the solidified layer (8) becomes larger than the thickness of the metal strip (9) to a certain extent. If the rolling blade is not thick, there is a risk that cracks may occur in the metal strip that has been pulled out.

The present invention has been made in view of the above-mentioned points of view, and is aimed at preventing cracks from occurring in metal strips when the metal strips are continuously cast using a twin-roll continuous casting machine.

According to the present invention, the rolling blade on which the solidified layer is rolled by the rolls is measured, and if the rolling force is larger than a predetermined value, the cooling length of the molten steel by the rolls is shortened, and if the rolling force is smaller than the predetermined value, the rolling blade is Casting is carried out by continuously pulling out the metal strip from the roll gap while moving the barrel seal so as to extend the cooling length of the molten steel by the rolls.

Therefore, the quality of the product is improved because cracks and the like do not occur in the drawn metal strip.

Embodiments of the present invention will be described below with reference to the drawings.

Roll +1) (2) Shaft box θ0) pivoted on both sides of the shaft
(11) is equipped with a load detector (121 (+31) such as a load cell for measuring the rolling force, and the load detector (
121 (Put the tip of the screw shaft 0ω in contact with the end of 13+,
By rotating the screw shaft oao9 by an appropriate means, the gap G between the seal rolls (1) and (2) can be adjusted to a predetermined value, and the fluid pressure cylinder uoaη is connected to the barrel seals (3) and (4). The fluid pressure cylinder (16)
←The barrel seals (3) and (4) can be moved back and forth by force. Also, the side seal (5) is rolled (1) (2) with a constant force by a fluid pressure cylinder (6), similar to the one shown in Fig. 2.
It is designed so that it can be pressed against the side surface.

When continuously casting metal strips using the above-mentioned twin roll continuous casting machine, the gap G between the rolls (1) and (2) should be cast by rotating the screw shafts (14) and (151). The drive unit rotates the roll (11 (2+) at a constant circumferential speed, and the side seal (6) is attached to the roll (1) by the fluid pressure cylinder (5).
While pressing with a constant force against the side of f2), the barrel seal (3) (
The work is carried out while moving the roller (4) in a direction perpendicular to the axis of the roll (1) f2) according to the rolling blade. In other words, the molten steel (force) is supplied by appropriate means to the space above the rolls (1) (2), which are stacked four times by the barrel seals (3) (4) and side nols (5). ) is cooled to form a solidified layer (8) on the surface of the roll (1).
(2), it is pulled out to become a metal strip (9). During such continuous casting, in order to prevent the unsolidified layer from leaking from both sides in the width direction of the metal strip, causing a burr on the end surface or a defect in the shape of the end surface, the unsolidified layer is The casting operation must be performed while the lowest end position P of the roll (21) is the same as the center position of the roll (1) (21), or the center position of the roll (1) (2) is also located above. The total thickness of the coagulated layer (8) is larger than the thickness of the metal strip (9), and the coagulated layer (8) is formed by the roll (]) (2
) is rolled when passing through the gap G.

The rolling blade when the solidified layer (8) is rolled is the load detector GH.
31 and sent to an arithmetic and control unit (not shown).
The arithmetic unit compares it with a predetermined rolling blade corresponding to the thickness of the metal strip (9). If the rolling blade is larger than a predetermined value, the total thickness of the solidified layer (8) to be rolled is too large, so the cooling length L of the molten steel (7) by the roll f102+ must be shortened. Therefore, the rond of the fluid pressure cylinder (16) 0η is extended in accordance with the deviation ΔF between the measured reduction blade F and the set reduction blade Fo, and the cooling length L is shortened. Also, if the rolling blade is smaller than the predetermined value, the thickness of the solidified layer (8) to be rolled is too small, so the cooling length L of the molten steel (7) by the roll (1) (2+) is extended. Therefore, the rond of the fluid pressure cylinder u[1)07) is reduced in accordance with the deviation ΔF between the measured reduction blade F and the set reduction blade Fo.
The cooling length L is extended.

The control state during such casting will be explained with reference to FIG. 4. When the measured reduction blade is Fo + ΔF, the left and right rolls (
Il (If the distance from the center of the gap in 21 to the barrel seal is J, the fluid pressure cylinder is controlled so that 11 (If the distance from the gap center of 2+ to the barrel seal is x2, then 22 = Z (1 - Δ
The fluid pressure cylinder is controlled so that it becomes 2. However, Δ2
is the deviation.

With this method, without changing the peripheral speed of the roll, which has poor response speed, and without changing the roll gap or plate thickness,
Metal strips can be continuously cast, and even when there are disturbances such as fluctuations in molten steel temperature, completely solidified plates can be continuously cast by adjusting the cooling length.

In addition, in the embodiment of the present invention, the case where the side seal is swung left and right has been described, but it is also possible to implement the [b] formula, and other changes may be made without departing from the gist of the present invention. Of course, it is possible to add .

According to the continuous casting method in the twin-roll continuous casting machine of the present invention, since the solidified layer can be pulled out while being rolled by the optimal rolling blade, there is no possibility that the unsolidified layer will leak from the end face in the width direction of the metal strip. No cracks occur in the metal strip,
Therefore, the product quality is improved, the yield is improved, and various excellent effects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a continuous casting method using a twin-roll continuous casting machine that has been proposed so far, Fig. 2 is a view from the ■-■ direction arrow in Fig. 1, and Fig. 3 is a twin-roll continuous casting method of the present invention. FIG. 4, which is an explanatory diagram of the continuous casting method in the type continuous casting machine, is a graph for explaining the case where the cooling length of the roll is controlled in the method shown in FIG. 6. In the figure (11 (21 is a roll, (3), (4) is a barrel seal, (5) is a side seal, (7) is molten steel, (8) is a solidified layer, (9) is a metal strip, H (13 ) is a position detector,
(14) (15) is a screw shaft, (161 (l force) indicates a fluid pressure cylinder. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd. 3 Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] 1) A plurality of rolls are arranged in parallel, molten steel is supplied to a space surrounded by a barrel seal arranged on the rolls and a side seal arranged on the side of the rolls, and a metal strip is continuously passed through the roll gap. In a twin-roll continuous casting machine designed to pull out the solidified layer by the rolls, the rolling edge where the solidified layer is rolled by the rolls is measured, and if the rolling edge is larger than the prescribed rolling edge, the barrel seal is moved to the roll gear rough side. If the rolling blade is smaller than the predetermined rolling blade, move the barrel seal away from the roll gap 1 side to lengthen the cooling length of the molten steel by the rolls. A continuous casting method using a twin roll continuous casting machine, which is characterized by continuously casting strips.